1. Field of the Invention
The present invention relates to multi-layer composite electronic components such as multi-layer duplexers, multi-layer triplexers, multi-layer diplexers, and multi-layer filter arrays, which are constructed for use in microwave bands.
2. Description of the Related Art
A conventional multi-layer composite electronic component has a structure shown in each of FIGS. 9 and 10. As shown in FIG. 9, a multi-layer composite electronic component 1 includes a ceramic sheet 6 having inductor patterns 12 to 17 disposed thereon, a ceramic sheet 7 having capacitor patterns 18 to 23 disposed thereon, a ceramic sheet 5 having coupling capacitor patterns 24 to 27 disposed thereon, a ceramic sheet 3 having shield patterns 28a and 29a disposed thereon, and a ceramic sheet 9 having shield patterns 28b and 29b disposed thereon.
On the left-half region of the duplexer 1, a three-stage band pass filter circuit BPF 1 including LC resonators Q1 to Q3, is provided. On the right-half region of the duplexer 1, a three-stage band pass filter circuit BPF 2 including LC resonators Q4 to Q6, is provided. Inductors L1 to L6 of the LC resonators Q1 to Q6 are defined by inductor patterns 12, 13, 14, 15, 16, and 17. Capacitors C1 to C6 of the LC resonators Q1 to Q6 are defined by capacitor patterns 18, 19, 20, 21, 22, 23 and the top-end portions of the inductor patterns 12, 13, 14, 15, 16, and 17 opposing the capacitor patterns 18 to 23.
In addition, the LC resonators Q1 to Q3 of the band pass filter circuit BPF 1 are electrically coupled by coupling capacitors Cs1 and Cs2 defined by the inductor patterns 12 to 14 and coupling capacitor patterns 24 and 25 opposing the inductor patterns 12 to 14. Shield patterns 28a and 28b are provided with the patterns 12 to 14, 18 to 20, 24, and 25, disposed therebetween. Similarly, the LC resonators Q4 to Q6 of the band pass filter circuit BPF 2 are electrically coupled by coupling capacitors Cs3 and Cs4 defined by the inductor patterns 15 to 17 and coupling capacitor patterns 26 and 27 opposing the inductor patterns 15 to 17. Furthermore, shield patterns 29a and 29b are arranged with the patterns 15 to 17, 21 to 23, 26, and 27 disposed therebetween.
As shown in FIG. 10, a multi-layer body 35 formed by laminating ceramic sheets 2 to 9 includes a transmission terminal electrode Tx, a reception terminal electrode Rx, an antenna: terminal electrode ANT, and ground terminal electrodes G1 to G4. The transmission terminal electrode Tx is connected to the inductor pattern 12 of the LC resonator Q1, the reception terminal electrode Rx is connected to the inductor pattern 17 of the LC resonator Q6, and the antenna terminal electrode ANT is connected to the inductor patterns 14 and 15 of the LC resonators Q3 and Q4, respectively. The ground terminal electrodes G1 and G2 are connected to one end of each of the inductor patterns 12 to 14 and one end of each of the capacitor patterns 18 to 20 of the LC resonators Q1 to Q3. The ground electrodes G3 and G4 are connected to one end of each of the inductor patterns 15 to 17 and one end of the capacitor patterns 21 to 23 of the LC resonators Q4 to Q6.
Meanwhile, in the conventional duplexer 1, the inductor patterns 12 to 14 constituting the band pass filter circuit BPF 1 and the inductor patterns 15 to 17 constituting the band pass filter circuit BPF 2 are arranged parallel to each other on the same plane of the ceramic sheet 6. With this arrangement, magnetic field components generated on the inductor patterns 12 to 14 and magnetic field components generated on the inductor patterns 15 to 17 are also parallel to each other. As a result, the band pass filter circuits BPFs 1 and 2 tend to be electrically coupled with each other, thereby leading to changes in the filter characteristics of the band pass filter circuits BPFs 1 and 2.
In order to prevent the above problems, it is necessary to increase the space between the band pass filter circuits BPFs 1 and 2, or it is necessary to dispose a shield pattern between the band pass filter circuits BPFs 1 and 2. However, such measures are not effective enough to reduce the electric coupling between the band pass filter circuits BPFs 1 and 2, and another problem such as an increase in the size of the duplexer 1 is caused due to the extra space or the shield pattern.
To overcome the problems described above, preferred embodiments of the present invention provide a compact multi-layer composite electronic component in which electric couplings between a plurality of high-frequency circuits contain ed therein are greatly reduced.
To this end, according to one preferred embodiment of the present invention, there is provided a multi-layer composite electronic component including (1) a multi-layer body defined by laminating a plurality of insulating layers, a plurality of inductor conductors, and a plurality of capacitor conductors, (2) a first high-frequency circuit having a plurality of LC resonators including a plurality of inductors defined by the inductor conductors and a plurality of capacitors defined by the capacitor conductors, and (3) a second high-frequency circuit having a plurality of LC resonators including a plurality of inductors defined by the inductor conductors and a plurality of capacitors defined by the capacitor conductors. In this multi-layer composite electronic component, at least one of the inductors of the first high-frequency circuit is disposed substantially perpendicularly to at least one of the inductors of the second high-frequency circuit.
Since at least one of the inductors of the first high-frequency circuit is arranged substantially perpendicularly to at least one of the inductors of the second high-frequency circuit, the magnetic-field components generated around each of the inductors are also substantially perpendicular to each other. As a result, the electric couplings between the inductors are minimized.
Other features, elements, characteristics and advantages of present invention will become apparent from the following detailed description of preferred embodiments thereof with reference to the attached drawings.